Due to un-uniformity of rice grader practices in Malaysia, zones which actively producing rice in Malaysia are using their own way of grading rice.
The laboratory analyses were performed in the Rice Research Institute of Iran (RRII). The evaluated rice variety, Hashemi, is one of the common varieties of rice in north of Iran (Zareiforoush et al. 2010b). This variety is categorized as “long kernel” rice according to the standard provided by the Institute of Standards and Industrial Research of Iran (ISIRI) (ISIRI 2012). Moisture content of the evaluated samples was determined by means of a digital moisture meter (GMK model 303RS, Korea) to be 11–13.5 % (w.b.). Before image acquisition, milled rice grains were classified by milling experts into four classes based on the standard provided by ISIRI (ISIRI 2012). The classes included Low-processed sound grains (LPS), Low-processed broken grains (LPB), High-processed sound grains (HPS), and High-processed broken grains (HPB). The mentioned grades were defined based on two quality indices, namely degree of milling and length of rice grains.
Performance was evaluated for 3 kg of locally milled rice samples based on the design capacity of the machine, cleaning efficiency and degree of grain flow. The result showed that the design capacity (1.8 kg/h) of the modified rice destoner was higher than that of the existing (0.86 kg/h). Also, the modified machine has 40.8% destoning efficiency which is higher than that of existing machine (2.58%).